More than 99 percent of Antarctic blue whales were killed by commercial whalers during the 20th century, but the first circumpolar genetic study of these critically endangered whales has found a surprisingly high level of diversity among the surviving population of some 2,200 individuals.

A new study suggests that the impact of predation on juvenile Steller sea lions in the Gulf of Alaska has been significantly underestimated, creating a “productivity pit” from which their population will have difficulty recovering without a reduction of predators.

A spectacular display of nature’s sometimes cruel cycle of life was witnessed by beachgoers at Blue Cliffs Beach in Tuatapere, New Zealand when orcas, also known as killer whales, forced a group of large sharks to swim into shallow waters or risk being eaten.

Cetology is a branch of marine mammal science that studies about eighty species of dolphins, whales, and porpoise, all of which are classified within the Cetacea order. Cetologists, who practice cetology, work to understand the distribution, development, behavior, and other aspects of cetaceans.
The study of cetaceans began in the Classical era. About 2,300 years ago, Aristotle documented details about some cetacean species, calling them mammals, while traveling on the Aegean Sea with...

Dall’s porpoise (Phocoenoides dalliz) can only be found in the North Pacific, with a range that includes the Sea of Japan and the Okhotsk and Bering Seas. This range extends to southern California in the east and to the southern waters of Japan in the west. When normal weather patterns change and waters become colder, this species can be found in in Baja, California, specifically in Scammon's Lagoon, and strays can occasionally be found in the Chukchi Sea. It prefers to reside in cold...

Image Caption: Fossil of Feresa Attenuata, Shimonoseki Marine Science Museum KAIKYOUKAN, Japan. Credit: OpenCage/Wikipedia (CC BY-SA 2.5)
The pygmy killer whale is widely distributed in tropical and sub-tropical waters worldwide. Regular sightings of this species occur off the coast of Hawaii and Japan, and also in the Indian Ocean near Sri Lanka and Lesser Antilles. In the Atlantic the pygmy killer whale has been seen off the coast of South Carolina and Senegal. This species swims in...

The Ross seal (Ommatophoca rossii) is a true seal in the Phocidae family, and can only be found on pack ice in Antarctica. This species was formally described by James Clark Ross in 1841, during his British Antarctic Expedition. It is very uncommon to see in its range and rarely leaves the pack ice, with stray individuals occurring off southeast Australia or sub-Antarctic islands.
The Ross seal can reach an average length between 5.5 and 6.9 feet, although some females can reach up to 8.2...

The crabeater seal (Lobodon carcinophagus) is a true seal that can be found around the whole of Antarctica. Its range also includes small areas in South America, New Zealand, Africa, and Australia. It resides on the pack ice zone for the entire year, even as it shifts seasonally, and prefers to stay in the continental shelf area in water with a depth of less than 1,968 feet. Because the populations are so wide spread and are sufficiently mixed, there have been no subspecies found.
Because...